Vacuum tube elements assembly



Sept. 1, 1936. w. L. KRAHL: VACUUM TUBE ELEMENTS ASSEMBLY Filed Oct. 26, 1929 I NVENTOR Z. Maw/4 Mia 727? ATTORNEY Patented Sept. 1, 1936 VACUUM TUBE ELEMENTS ASSEMBLY Walter Louis Kralil, Montclair, N. J., assignor,

by mesne assignments, to Arcturus Development Company, a corporation of Delaware Application October 26, 1929, Serial No. 402,558

13 Claims.

This application relates to vacuum tubes and particularly to a means and a method for 'assembling the various elements into a compact unit. a

One of the objects of the invention is to provide a unitary element structure which maybe rigidly assembled entirely independent'of the stem of the vacuum tube upon which it may be subsequently supported. I 4 7 Another object of the invention is to provide means to attach the elements of a vacuum tube to a plurality of spaced insulators. I

' A further object of the invention is to provide a unitary tube element structure using a pair of spaced insulating member in which one ofthe insulating members is an exact duplicate of the other. 7 7

Another object of the invention is to provide a novel means to attach the cathode of a vacuum tube to a pair of spaced insulating members.

, Another object of the invention is to provide a unitary element structure for vacuum tubes which will permit the use of a stem having straight support rods sealed therein.

Still another object of the invention is to provide a unitary structure for the elements of a vacuum. tube which will permit the use of a stem having support rods sealed therein which are exactly the right length to connect with the various elements and need not be bent or cut off.

after the press is formed. 7

A still further object of the invention is to provide a novel means of rigidly supporting a mesh anode in a vacuum tube.

Other objects of the invention and objects relating particularly to the method of constructing and assembling the various elements will be apparent as the description of the invention proceeds.

' The invention has been illustrated in the accompanying drawing in which:

' Fig. 1 is a front elevation of a vacuum. tube showing the glass bulb in dot and dash line and with certain portions in section to more clearly illustrate the construction.

Fig. 2 is a sectional view of the element structure taken on the line 2-.2 of Fig. 1;

Fig. 3 is a plan view of the element structure;

Fig. 4 is a sectional plan View of theelement structure taken on the line 4+4 of Fig. 1;

Fig. 5 is a perspective. view of the member used to attach the anode element to the insulating plates; and

Fig. 6 is a perspective view of a modified form of anode showing the means of attaching to the insulating plate.

Referring now more specifically to Fig. 1 the invention has been shown in connection with a vacuum tube having a glass envelope ll] mounted 5 on the usual base I I to which is attached the terminals of the tube. A glass press I2 is formed integral with the envelope [0 as is the usual custom and serves to support the elements of the tube. 10

These elements comprise an anode [3 a grid I4, a cathode l5, and a filament l6 separated from the cathode by a pair of insulating. sleeves H.

The anode I3 I preferably form of wire mesh to increase the surface thereof and for other reasons, and this wire mesh is rolled in the form of a cylinder having flanges l8 which are brought together and attached to secure the wire mesh in the cylindrical form. In order to support the anode in position in the tube and spaced properly from the other element, I provide a member l9 at each end thereof. This member comprises a ring of sheet metal having a flange 2| on the inner edge thereof extending at right angle to the ring 20. On the outer edge of the ring I provide a plurality of arms 22 which are bent at right angle to the ring 20 in the opposite direction from the flange 2|. For convenience-I prefer to use three of these arms spaced apart at 120 although any desired number may be used. A portion 23 of each arm adjacent the end thereof is narrower than the portion adjacent the ring 20 forming a shoulder 25 against which is adapted to rest an insulating member in a manner to be hereinafter described. A flat member 26 is preferably formed integral with the ring 20 and extends outwardly in the same plane thereof. This member is provided with a pair of wings 21 which are adapted to be bent downwardly over the edges of the flanges l8 which are formed on the anode so that the member 26 forms an additional means of securing the member l9 to the anode cylinder. The member 26, may of course, be welded or otherwise secured to the flanges [8 by means of the wings 21.

To hold the anode cylinder in place I provide a pair of insulating plates 28 formed of anyinsulating material having a high melting. point which is free from gas at high temperatures such as isolantite', quartz, mica, crolite and the like. These plates may be exactly alike and may be of any desired shape although I prefer to make them circular with portions extending on opposite sides as clearly indicated in Figs.'3 and 4. These ininsulated from the cathode.

sulating plates 28 are provided with slots 29 arranged tangentially to a circle whose center is the center of the plate and spaced at intervals of around the circle. These slots are just large enough to receive the ends 23 of the arms 22 on the member l9 and the arms 23 are long enough to extend through the openings 29 and are adapted to be bent over on the other side holding the plate securely against the members l9, the shoulders 25 on the arm 22 resting against the inner side of the plate. means to hold the two insulating plates in spaced relation to each other and rigid with respect to the anode.

Each of the plates 28 is provided with a hole 30 in the center thereof adapted to receive a tubular cathode I5. The cathode i5 is adapted toextend through both of the plates and toiprotrude beyond the plates and at the top it may be belled slightly as at 3| to prevent it from slipping .down'through the upper plate. At the bottom it may be attached to a strap 32 which is adapted to contact with the lower plate .and prevent the cathode from moving upwardly. I also provide the plates 28 with a slot 33 spaced from the cathode hole 30 and adapted to receive either of the flat ends 34; or 35v of a grid support rod 36 to which is welded or otherwise secured a helical grid M. .The slots 3'3.in.the plates 28 prevent. this post 36 from rotating and therefore maintain the helical grid [4 in spaced relation to the cathode and anode.

Inorder to .heat the. cathode I preferably provide a hairpin filament I6, each leg of which is provided with a very thin insulating sleeve H The lower ends of the filament may be bent outwardly as indicated in Fig. 1 to hold the sleeve in'place thereon. This filament and insulating sleeve construction forms the subject matter of a co-pending application entitled, fMeansof supporting filaments ,in thermionic tubes, filed Oct. 26, 1929, Serial No. 402,557. d

Thus described the anode ,l3.,,the grid M, and the cathode l5, together with the spaced insulating plates 28 form aunitary element structure. The filament [6 together with its insulating sleeves l'l may be included in this structure if desired, by providing a small enough cathode so that thevinsulatingsleeves i l are rrictionally held inplace. thereby or the filament and sleeves may be inserted when the element unit is mounted in a tube. l

In assembling the structure the anode i3 will first be provided with its ring members ,I 9 welded thereto at each end and the upper insulating plate maypthen be attached to the anode by the insertion of the ends 23 of the arms 22 on the ring member l9 through the slots 29 and bending the ends over on theopposite side of the insulator as shown in Figs. 1 2, and 3. The gridmay then be placed in position by inserting the upper flattened end of the grid post 36 into the slot 33' provided for it in the upper plate 28.- Next the lower insulating plate 38 withthe cathode-30 previously inserted in the center hole and the arm 32 welded to it maybe placed in position inserting; the ends 23 of the arms 22 into their cooperating slots 23 and bending them over. I With the insulating plates inispaced relation. the grid is held between the two by the unflat-.

'tened portion comingin contact with the inner sides of the plates and a slight clearance is preferably left so that-the grid may expand upand down a short distance.

The filament together with its insulating sleeve Thus the anode forms a ture. Near the center of the pressI preferably provide two short'support rods 39 for connecting a I to the filament, these rods being spaced apart so that the ends of the filament may be, bent outwardly as already mentioned above. Adjacent the support rod 38 I provide another short support rod '4!) for making the grid connection. In forming the stem these various support rods, already cut to their proper lengths, may be mounted in a fixture for that purpose and the glass 'sealed around them whereupon the stem is ready to receive the elements.

Each of the insulating plates 28 may be provided with an opening ll and another opening 42 diametrically opposite each other'and spaced somewhat from the circle made by the cylindrical anode. The holes 4! are adapted to cooperate with the support post 31 and the holes 42 are adapted to cooperate with the support post 38 so that when the elements are mounted upon the stem it is only necessary to slip the two insulating plates with their assembled elements over the ends of the support rods 31 and 38 until the elements reach their proper-position with respect to. the press when the flanges l8 on the anode may be Welded to the support 33 against which they will be found to lie. Thisholds the whole element structure rigid. Another weld maybe made between the strap 32 and the support 37, the end of the strap 32 being formed to fit part way around the support 31inorder to make a good electrical contact therewith, and .the' ends of the filament l6 are then welded to the support 39 against which they will be found to lie. Also 'a strap 43 may be welded between the short upright it and the flattened end 34 of the grid post 36.

The cathode is electrically connected to the support 31 by means of the strap 32 and the support.

31 may be connected by means of a wire 44 to the base terminal 45 which forms the cathode con nection for the tube. In like manner the grid post 46 is connected to the grid by the strap 43 and a wire 46 may be provided for connecting the support 48 to the grid terminal .47 at the baseof the tube. The two filament posts 39 may be con: nected by means 'of'the wires 48 to the two fila ment terminals '49. An excellent electrical con-. nection is made between the'anode at thesu'pe port post 38 by means of the flanges l8'as mentioned above and a wire 50 maybe provided to connect the supporting post 38 with the anode terminal 5I' at the base of the'tube. The base terminals may of course; be arranged in any desired manner the showing in Fig. 1 being made solely for illustrating the various connections.

It will be seen from the above description that While the anode is shown as made of wire mesh 7 it is evident that a solid plate anode as Elia, Fig. 6,

might be used in which case the ring 19 would not be necessary but the arms '22 could be formed directly on the anode cylinder as arms 22a having shoulders 25a and end portions 23a. I

It will be evident that the structure just described is very simpleconsisting of a minimum of parts and necessitating very few operations for assembling the parts and very few welds; The construction forms a strong element unit in which the elements are maintained rigidly with respect to each other and cannot possibly get out of alignment, thereby insuring a tube having constant characteristics and one particularly adapted to mass production. The assembling of the parts may be made with practically unskilled labor as it isalmost impossible to get the parts together in any but the right way.

Many modifications may be made in the construction as shown and described-and I do not, therefore, wish to limit myself to the construction-as'shown in'the drawing except as such limitations as contained in the appended claims:

What I claim is:

1. In a unitary element structure for vacuum tubes a tubular anode, a reinforcing member securedat each end of said anode, arms on said reinforcing member, an insulating member spaced at each end of said anode and having openings to receive the ends of said arms, shoulders on said arms against which said insulating members are adapted to rest, the ends of said arms being bent over to hold said insulating members in place,

a cathode extending through openings in said insulating members and spaced from said anode, means to hold said cathode in place, a grid positioned between said anode and cathode, a support for said grid extending between said insulating members and protruding through openings provided for that purpose, and a filamentary heater positioned within said cathode.

2. In a unitary vacuum tube element structure a tubular anode of wire mesh, a reinforcing element attached to each end of said anode, a plurality of arms extending outwardly on said reinforcing element and longitudinally of said anode, shoulders on said arms, an insulating member at each end of said anode having openings to cooperate with said arms, said insulating members being adapted to rest upon said shoulders, and said arms being'bent over said insulating members to hold said insulating members in place, a helical grid mounted adjacent said anode, a support rod for said grid and extending through openings in each of said insulating members, the ends of said support rod being flattened to prevent rotation of said support rod, a cathode within said helical grid and extending through openings provided for that purpose in said insulating members, means to prevent said cathode from longitudinal movement in said insulating members, and a filament within said cathode to heat it.

3. ma vacuum tube a press, a pair of relatively long supporting posts sealed in said press and spaced apart, a pair of relatively short posts sealed in said press adjacent the center thereof, a fifth relatively short support post sealed in said press, a pair of insulating members, three vacuum tube electrodes spaced between said insulating members and rigidly secured in position thereby, said insulating members having openings adapted to receive said relatively long supporting posts through which said supporting posts extend, means attached to one of said tube elements and to one of said relatively long supporting posts for making electrical connection therebetween, means attached to another of said tube elements and to the other of said long supporting posts for making-electrical connection therebetween, means connecting the third of said tube elements to said fifth supporting post for malnng electrical connection therebetween, and a self-supporting filamentary unit heater posi tioned adjacent one of said tube elements and electrically connected to said pair of relatively short supporting posts.

4. In a vacuum tube a press, a pair of relatively long supporting posts sealed in said press, a pair of insulating members, a tubular anode positioned between said insulating members, said anode having a flange extending longitudinally on one side thereof, a cathode within said anode and extending through openings in said insulating members, a helical grid surrounding said cathode, a supporting post within said grid extending through openings provided for that purpose'in said insulating members, said insulating members having openings toreceive said relatively long supporting posts through which said posts are adapted toextend, one of said posts being welded to said anode flange, means to connect one end of said cathode to the other of said supporting post, a relatively short supporting post sealed in said press, means to connect said relatively short post to said grid support, a pair of relatively short supporting'posts sealed in said press and positioned in the center thereof, and a self-supporting filamentary unit within said cathode and attached to said pair of relatively short support posts.

5. A means to attach a tubular anode to a perforated insulator which comprises in combination with a tubular anode and a perforated insulator, of a short cylindrical member adapted to conform to the surface of said anode, a flange on said member adapted to rest upon the end edge of said anode, a plurality of arms extending longitudinally of said cylindrical member from said flange, shoulders on said arms against which said insulator is adapted to rest, the ends of said arms adapted to pass through the perforation of said insulator, and additional means for securing said members to said anode.

6. In a unitary vacuum tube element structure an insulating member, a tubular element having a flange extending longitudinally thereof and a short tubu ar member adapted to conform to the surface of said element adjacent one end thereof, a flange on said tubular member adapted to extend over the edge of said element, arms on said flange extending longitudinally of said element whereby said element may be attached to said insulating member, and additional means on said member to attach to said element flange.

7. In a vacuum tube element structure a cylindrical element of wire mesh, a radial flange extending longitudinally on one side of said element, a short cylindrical member adapted to fit inside of the end of said element, a right angle flange on said member adapted to extend over the end of said element, arms on said member extending longitudinally of said element and adapted to cooperate with an insulating member and hold it in position with respect to said element, an arm extending from said flange over said longitudinal element flange, and a pair of fingers extending down the side of said flange and attached thereto.

8. A radio tube including an anode plate, a grid, a tubular cathode element, together with an insulating plate at the top of said anode plate positively engaging all three elements to maintain them in proper spaced relation with respect to-ieach other, the tubular'cathode element passing through an opening in the top insulating plate and having a projecting endmade with an enlarged portion SOI that it will not pass through the opening in the insulating plate,

9. A radio tube including an anode plate, 'a grid, a tubular cathode element, an insulated plate secured to the anode plate and, positively engaging all three tube elements to maintain them in proper spaced relation with respect to each ether, the cathode element passing through an opening in the insulating plate, and having a distorted portion adapted to restrain the cathode from movement through the opening. 7

10. A radio tube, including an anode plate, a grid, a tubular cathode element, an insulated plate secured to the anode plate and positively engaging all three tube elements to maintain them in proper spaced relation with respect to each other, and means for preventing movement of the cathode element in at least one direction with reference to said plate.

11. A radio tube including an anode plate, a grid, a tubular cathode element, an insulated plate secured to the anode plate and positively engaging all three tube elements to maintain then; in proper spaced relation withtrespect to each other, the cathodeelementpassing through an opening in the insulating plate, and-means ,for preventing movement pf the cathode jelement through said opening in a direction toward. the ube m- 12. A radio tube including an anode plate, 'a grid, a1 tubular cathode element, an insulated plate securedto the anode plate and positively engaging all three tube elements toamaintain them in -proper spaced relationwith respect to each other, the cathode element passingthrough an opening inthe insulating plate, means for preventing movement of the-cathode element through said opening in a direction toward the tube stem, and additional means for preventing cathode movementaway from said stem,

13, A radio tubeincl-uding an anodeplate, a grid, -a tubular cathode element, an insulated plate secured 130 the anode; plate and positively engaging all three tube elements to maintain them improper spaced relation with respect to each other, and means for supporting the cathode element from-said insulated plate.

W LT R LOUIS KRAVHL. 

